Utility model 9101848 of the same applicant claims a device for holding the film sideways in wrapping machines, which holding device relies upon a pair of clamps with which the film is held, which clamps are mounted upon supports travelling along tracks that allow the distance between the same to be varied, thereby adjusting perfectly to the type of roll to be used in each case, which adjustment is made fully automatically because of the mobility of the supports to which the film clamps are attached, and of the means working with such supports, such as racks, driving gears and so forth.
For its part, patent of invention 9201865, likewise of the same applicant, claims improvements precisely to film wrapping machines, applicable in means designed to control the reciprocating travel of a rod which limits the length of the film sector to be used to wrap each product or article, the above in order to have the film sheared at the specific length to be used for wrapping purposes.
Neither of the above devices has means enabling the film replacement operation to be controlled, nor are they fitted with means for weighing the wrapped products, specifically the trays containing such products and wrapped with the film as such.
Furthermore, known machines are constructed in such a way that it is if not impossible very difficult to be able to carry out overhauls and manipulations required to maintain machines of this kind.
Reference might also be made to Spanish patent of invention number 8700493 which also deals with a machine of the subject type, which includes a lifting arm, where the said lifting arm is appropriate only for certain tray sizes, and cannot handle larger sizes and hence does not allow the machine to be fitted with an automatic system for changing the size of the tray to be wrapped.
None of the above machines have automatic film replacement means when the size of the product to be wrapped is changed, nor indeed means allowing merely the initial assembly of the film or replacement thereof when a roll is used up and replaced with another.